Improvements in a Thyristor Controlled Static on-Load Tap-Changer for Transformers

A new type of static on-load tap-changer based on forced commutation is suggested in this paper as a better alternative to the conventional type of tap-changers. The response of the proposed tap-changer is very fast. Any required amount of load voltage variation can be obtained without introducing any phase shift in the output voltage. Experimental verification of the basic principles have been carried out which establish the feasibility of the proposed scheme. A number of theoretical and experimental results are presented.